Alcohol and drug abuse among sexual minority women (SMW) is an increasingly recognized public health concern in the United States. Across a multitude of nationally-representative samples, SMW populations report higher rates of substance use and disorder (SU/D) across the lifespan, and further report greater levels of adversity in both childhood and adolescence as members of a stigmatized group.1,2 Although minority stress models suggest that higher levels of adversity may explain mental health disparity among sexual minority populations,3,4 few studies have examined the impact of adversity across development among SMW in predicting SU/D in later life; none have examined psychological mediators of this proposed pathway; and none have examined moderators of this developmental pathway. The goal of the present proposal is to examine the impact of adversity on psychological risk factors of SU/D across development and address protective factors that reduce risk for later SU/D among SMW. Specifically, the proposed study will test whether adversity and subsequent increases in emotion dysregulation (ED) among SMW in childhood and adolescence account for higher levels of SU/D through young adulthood, and will examine whether social support from peers and parents within adolescence buffers this proposed risk pathway. Data will be drawn from 2,278 heterosexual and 173 sexual minority women who participated in the Pittsburgh Girls Study. The Pittsburgh Girls Study is a large, diverse sample of inner-city girls followed prospectively from age 5 to age 23, and contains a large longitudinal sample of SMW ideal for addressing the proposed study aims. Factor analysis, latent growth curve modeling (LGM), and multi-group structural equation modeling (SEM) will be used to test 1) whether ED and adversity experiences in childhood and adolescence predict increases and higher levels of SU/D through young adulthood; 2) whether ED mediates the effects of adversity and SMW status on SU/D, and whether ED moderates the impact of adolescent adversity on SU/D; and 3) whether social support moderates the effect of ED and early and adolescent adversity on later SU/D across sexual orientation groups. Addressing these questions will inform both preventative and treatment intervention efforts to reduce the prevalence of substance disorder among lesbian, gay, and bisexual populations by informing the early identification of environmental risk factors associated with sexual minority status across development; by identifying target psychological processes that have a direct impact on substance use and disorder among lesbian, gay, and bisexual individuals; and by addressing risk and resilience in the context of social support within this at-risk population.